WorksheetsElec group quiz
Total questions: 125
Worksheet time: 1hrs 3mins
In a dry sump system, what is the primary purpose of multiple scavenge pumps?
To increase oil pressure in the main gallery
To actively remove oil from different engine areas under high G-forces
To cool oil more efficiently
To reduce oil foaming
What is the critical architectural limitation of splash lubrication?
Requires expensive filters
Fails when oil pools away from dipper on inclines
Creates excessive oil pressure
Uses too much oil
In a forced-feed industrial system, where should the pressure relief valve be located?
After the oil cooler
Between pump outlet and filter inlet
At the bearing feed lines
In the return line to the reservoir
What distinguishes a large 2-stroke diesel lube system from a petrol system?
Higher oil injection pressure
Oil is recirculated, not burned completely
Uses wet sump architecture
Has no external tank
What causes VVT slow response despite normal oil pressure?
Oil viscosity too low
VVT feed is downstream of restrictive passages
Pressure sensor calibration error
Scavenge pump inefficiency
A wet sump's pressure relief valve before the filter creates what critical feature?
Better oil cooling
A bypass path if filter clogs
Higher bearing wash
Reduced pump cavitation
In a motorcycle dry sump, why is the external tank often omitted?
Reduced cooling needs
Packaging constraints in frame
Lower manufacturing cost
Natural slosh protection
What happens if oil is too thick?
Fast flow
Slow flow
No pressure
Clean oil
Which part pushes oil through the engine?
Oil filter
Oil pump
Radiator
Piston
What happens during oil starvation?
More power
Clean oil
No lubrication
Better cooling
What does oil pressure show?
Oil color
Oil force
Engine size
Fuel level
What is the main function of the oil pump in an engine lubrication system?
To cool the engine block
To store engine oil
To circulate oil under pressure to moving parts
To filter dirt from oil
Which type of oil pump is compact, efficient, and suitable for engines with limited space?
Gear pump
Vane pump
Gerotor pump
Piston pump
What is the primary purpose of lubrication in an engine?
Increase engine speed
Reduce friction between moving parts
Increase fuel efficiency
Reduce exhaust noise
Which is a secondary function of lubrication?
Power generation
Heat removal
Air filtration
Fuel mixing
Which lubrication function helps carry dirt and soot to the filter?
Sealing
Cooling
Cleaning and suspension
Shock dampening
What is the oil that provides the best wear protection even at extreme temperatures?
Mineral oil
Synthetic oil
Semi-synthetic oil
Base oil
This refers to the lowest temperature at which vapors will ignite a momentary flame in the presence of an ignition source.
Pour point
Flash point
Breaking point
Turning point
These are chemicals mixed into the base oil to improve, reduce, or add new features to the oil which it naturally does not have.
Enhancers
Suppressants
Chemically engineered oil
Additive
This is the parameter of a fluid's resistance to flow, commonly known as thickness.
Fluidity
Runniness
Viscosity
Glueyness
A hydraulic system operating at elevated temperature requires minimal viscosity change with temperature. The most suitable oil selection would be:
Low ISO VG oil with low viscosity index
High ISO VG oil with low viscosity index
Appropriate ISO VG oil with high viscosity index
Highest ISO VG oil available
Which property is not directly considered when assigning an ISO VG grade to a lubricating oil?
Kinematic viscosity at 40 °C
Allowable viscosity tolerance
Viscosity–temperature relationship
Nominal viscosity value
Two lubricating oils have the same ISO VG grade but different viscosity indices (VI). Under increasing operating temperature, the oil with the higher VI will:
Experience a greater reduction in viscosity
Maintain viscosity more effectively
Become unsuitable for hydrodynamic lubrication
Show identical viscosity behavior
What is the primary function of engine oil in internal combustion engines?
Power transmission through pressurized fluid
Reducing friction and wear between moving engine parts
Extreme pressure lubrication for gear teeth
Providing hydraulic pressure for gear engagement
Which fluid is mainly responsible for transmitting power in hydraulic systems such as construction equipment and industrial presses?
Engine Oil
Gear Oil
Transmission Fluid
Hydraulic Fluid
What type of lubricant contains extreme pressure (EP) additives to protect gears under heavy load?
Engine Oil
Transmission Fluid
Hydraulic Fluid
Gear Oil
What does the acronym SAE mean?
Simplified Application of Engineering
Society of Automotive Engineers
Standardized Automation for Engineering
Society of Administrative Engineers
What is the naming scheme for multi-grade SAE classification?
[High-temperature Viscosity][W]-[Low Temperature Viscosity]
[Low-Temperature Viscosity]
[Low-Temperature Viscosity] [W]-[High Temperature Viscosity]
[High Temperature Viscosity]
Which factor is MOST important when choosing the right lubricant for a machine?
Color of the lubricant
Load, speed, and operating temperature
Brand popularity
Storage container type
What is the main purpose of applying lubricant in the right place?
To make the machine look clean
To reduce oil consumption
To ensure lubricant reaches the contact surfaces where friction occurs
To cool the surrounding air
Which of the following best describes the overall benefit of following all 4 R's of lubrication?
Increased machine noise
Higher energy losses
Smooth operation and longer machine life
Frequent machine breakdown
Which situation shows incorrect application of the 4 R's?
Using gear oil in a gearbox
Applying grease inside a bearing housing
Overfilling a bearing with grease beyond recommended amount
Lubricating a machine based on maintenance schedule
Which type of lubricating oil is obtained directly from refined crude petroleum?
Synthetic oil
Semi-synthetic oil
Mineral oil
Bio-lubricant
Which lubricating oil is best suited for extreme temperature conditions?
Mineral oil
Semi-synthetic oil
Vegetable oil
Synthetic oil
Semi-synthetic oil is a blend of:
Two synthetic oils
Mineral oil and vegetable oil
Mineral oil and synthetic oil
Crude oil and additives
Which lubricating oil usually requires more frequent oil changes?
Synthetic oil
Semi-synthetic oil
Mineral oil
Bio-synthetic oil
Which type of oil offers a balance between cost and performance?
Mineral oil
Synthetic oil
Semi-synthetic oil
Used oil
In an internal combustion engine operating under high load and low speed conditions, failure of the lubrication system most directly leads to which tribological regime, resulting in accelerated wear?
Hydrodynamic lubrication due to increased oil film thickness
Elastohydrodynamic lubrication caused by elastic deformation
Boundary lubrication due to insufficient oil film separation
Mixed lubrication with complete surface separation
Which statement best explains how engine lubrication contributes to temperature control beyond the cooling system?
Lubricating oil increases combustion efficiency, reducing heat generation
Lubricating oil absorbs frictional heat and transfers it to cooler engine regions
Lubricating oil prevents heat transfer between engine components
Lubricating oil converts thermal energy into mechanical work
Which lubrication function most directly contributes to improved volumetric efficiency in an internal combustion engine?
Contaminant suspension and filtration
Reduction of mechanical vibration
Heat dissipation from frictional interfaces
Sealing between piston rings and cylinder walls
What is tribology primarily concerned with?
Chemical composition of metals
Science of interacting surfaces in relative motion
Design of machine elements
Study of heat transfer in moving parts
Which of the following is not one of the three core components of tribology?
Friction
Wear
Lubrication
Corrosion
Which discipline of tribology focuses on the mathematical behavior of liquid lubricants between sliding surfaces?
Solid mechanics
Fluid mechanics
Material science
Chemistry
What is the primary function of lubrication in tribological systems?
Increase contact area
Reduce friction and wear
Increase temperature
Prevent motion entirely
Which branch of tribology primarily studies chemical reactions between lubricants and solid surfaces?
Solid mechanics
Material science
Chemistry
Fluid mechanics
In which direction does the force of friction always act?
In the same direction as the applied force
Perpendicular to the direction of motion
Opposite to the direction of motion or applied force
Downward toward the center of the Earth
Which type of friction must be overcome to get a stationary object to start moving?
Kinetic Friction
Static Friction
Rolling Friction
Fluid Friction
According to Amonton’s First Law, frictional force is directly proportional to what?
The apparent area of contact
The velocity of the sliding object
The normal load (Normal Force)
The temperature of the surfaces
If the apparent area of contact between two sliding surfaces is doubled, how does the frictional force change (according to the Second Law)?
It doubles
It is cut in half
It remains independent of the area
It fluctuates based on velocity
What is another name for the resistance experienced by an object moving through a liquid or gas?
Sliding Friction
Viscous Friction
Rolling Friction
Static Friction
What is wear in mechanical engineering?
Sudden breaking of materials
Gradual loss or damage of material due to contact
Increase in material strength
Expansion of metal due to heat
Why do mechanical engineers try to minimize wear?
To increase machine size
To improve appearance
To extend service life of machine components
To increase vibration
Which type of wear is caused by hard particles or asperities scratching a surface?
Adhesive wear
Abrasive wear
Corrosive wear
Fretting wear
Which wear occurs due to repeated cyclic loading that leads to crack formation?
Erosive wear
Abrasive wear
Surface fatigue wear
Adhesive wear
What are the two classifications of tribology analysis?
Friction and Lubrication Analysis
Friction and Wear Analysis
Wear and Lubrication Analysis
Wear and Surface Analysis
An instrument that measures tribological quantities, such as coefficient of friction, friction force, and wear volume, between two surfaces in contact.
Tachometer
Friction meter
Tribometer
Wear tester
Method used to test lubrication properties of lubricants (oils and greases) under extreme pressure conditions.
Roller-on-roller
Pin-on-disk
Four-ball test
Thrust washer test
Surface roughness has three main parts: roughness, waviness, and ______.
Lay
Smoothness
Texture
None of the above
What is the main goal of selecting appropriate materials in surface engineering?
To reduce manufacturing cost only
To improve appearance without affecting performance
To minimize wear and energy loss by matching material properties to operating conditions
To replace the need for lubrication
Which factor is considered part of the operating environment in tribological testing?
Tensile strength
Fatigue resistance
Temperature and humidity
Surface hardness
Why are self-lubricating materials important in friction and wear considerations?
They increase surface roughness
They reduce the need for surface treatments
They help achieve low friction and high wear resistance
They improve color and gloss
What is the primary purpose of surface treatment?
To change the bulk properties of a material
To modify only the outer layer to enhance specific surface properties
To eliminate mechanical loads
To replace hard coatings
Nanotribology mainly focuses on studying friction and wear at what scale?
Millimeter scale
Micrometer scale
Atomic and nanometer scale
Macroscopic scale
Which combination best explains the role of tribology in biomedical joint implants?
High friction + high wear resistance
Low friction + controlled wear behavior
High lubrication + soft materials
Zero wear + rigid materials
Sustainable tribology primarily differs from conventional tribology by focusing on:
Increasing lubricant viscosity
Maximizing mechanical efficiency only
Reducing environmental and energy impact
Eliminating lubrication systems entirely
Which type of beam is fixed at one end and free at the other, commonly used in balconies and bridges?
Simply supported beam
Overhanging beam
Cantilever beam
Continuous beam
What is the purpose of the Factor of Safety (FoS) in engineering design?
To ensure that a product, system, or structure is safe
To reduce the cost of materials used
To make structures lighter and smaller
To increase the speed of construction
What term refers to the displacement or movement of a beam when it bends or sags due to applied loads?
Bending
Deflection
Strain
Stress
What do you call the deformation that occurs when a beam curves due to forces acting perpendicular to its length?
Torsion
Shear
Compression
Bending
Are the constants describing the mechanical response of a material when it is elastic.
Elastic Constant
Bulk Modulus
Young’s Modulus
Hooke’s Law
It is a principle of physics that states that the force needed to extend or compress a spring by some distance is proportional to that distance.
Poisson’s Ratio
Bulk Modulus
Shear Modulus
Hooke’s Law
It is the measure of the rigidity of the body, given by the ratio of shear stress to shear strain.
Hooke’s Law
Bulk Modulus
Shear Modulus
Elastic Constant
It is a type of elastic constant that describes the relationship between stress (force per unit area) and strain (proportional deformation in an object).
Rigidity
Young’s Modulus
Bulk Modulus
Stiffness
A structural member in a machine is subjected to a load that causes internal layers of the material to slide relative to each other without a significant change in length. Which loading condition best describes this behavior?
Tension
Compression
Shear
Torsion
Which loading condition is best characterized as a simultaneous presence of tensile and compressive stresses within the same structural element?
Compression
Torsion
Shear
Bending
A rotating shaft used in an electric motor primarily experiences which type of load, and What is the fundamental cause of this load?
Shear due to transverse forces
Compression due to axial loading
Torsion due to applied torque
Bending due to gravitational forces
Why is the study of strength and deformation of solids critical in mechanical engineering design?
It focuses only on material aesthetics
It eliminates the need for safety factors
It helps prevent structural failure while improving efficiency and cost-effectiveness
It applies only to civil engineering structures
What is stress in mechanics of materials?
Change in length of a material
Resistance of a material to heat
Force per unit area acting on a material
Ability of a material to return to its original shape
Which type of stress acts perpendicular to the surface of a material?
Shear stress
Normal stress
Thermal stress
Bending stress
Strain is best defined as:
Force applied to a material
Stress multiplied by area
Change in length divided by original length
Internal resistance per unit area
Which statement correctly describes elastic deformation?
The material breaks after deformation
The material permanently changes shape
The material returns to its original shape after load removal
The material deforms without stress
Which factor will increase the axial deformation of a bar subjected to a tensile load?
Higher modulus of elasticity
Shorter length
Larger cross-sectional area
Greater applied axial force
For two bars made of the same material and subjected to the same axial load, which bar will experience greater deformation?
The shorter bar
The bar with larger cross-sectional area
The longer bar
Both will deform equally
In a solid circular shaft under pure torsion, the maximum shear stress occurs at:
The center of the shaft
Half the radius
The outer surface
Uniformly throughout the cross section
For the same material, length, and applied torque, which shaft will twist more?
Solid shaft
Hollow shaft with large outer diameter
Hollow shaft with small outer diameter
Shaft with larger polar moment of inertia
What is the main purpose of surface hardening, and which parts commonly use it?
To soften the surface; used in jewelry
To increase surface hardness and wear resistance; used in gears and shafts
To change metal color; used in decorative items
To make the whole metal brittle; used in structural beams
What is the difference between coatings and surface layers?
Coatings are added materials; surface layers modify the original material
Coatings are thicker; surface layers are always thin
Coatings protect against heat; surface layers protect against chemicals
There is no difference
Which of the following is an example of a protective coating?
Titanium nitride layer
Paint, epoxy, or zinc coating
Non-stick cookware coating
Electroplated gold
What is the purpose of surface texturing?
To make the metal visually shiny
To reduce friction, improve lubrication, and enhance wear resistance
To increase the metal’s core hardness
To make thin-film coatings unnecessary
A surface exhibits a predominant direction in its texture due to a specific manufacturing process. Which geometric term best defines these characteristics?
Waviness
Surface roughness
Lay
Asperity
During elastic deformation of a surface asperity, what happens at the atomic level when the load is removed?
Atomic planes have slid past one another, creating a permanent offset
The atoms return to their original equilibrium positions due to interatomic forces
The asperity remains flattened to minimize surface energy
The surface energy of the asperity increases to satisfy broken bonds
If a material has very high surface energy, what is most likely observed chemical behavior when it is exposed to air?
It will remain chemically inert to preserve its energy state
It will oxidize rapidly to satisfy the dangling surface bonds
It will undergo elastic deformation spontaneously
Its waviness will decrease to zero
Waviness differs from surface roughness primarily in terms of:
The direction of the pattern
The presence of atomic sliding
The spacing of surface irregularities
The material’s reactivity to oxygen
Which of the following best describes the main difference between Primary Shaping Processes and Machining Processes?
Primary shaping removes material while machining adds material
Primary shaping gives basic shape with little or no material removal, while machining removes excess material for precision
Primary shaping is only for metals, while machining is for all materials
Primary shaping improves surface finish, while machining does not
Which machining process is most suitable for producing cylindrical surfaces, and why?
Milling, because it uses a rotating multi-point cutter
Shaping, because the tool moves linearly
Turning, because the workpiece rotates while the cutting tool removes material
Grinding, because it improves surface finish
Which of the following is a surface finishing process that improves surface quality using electrical current and an electrolyte?
Pickling
Polishing
Grinding
Electropolishing
Powder coating differs from painting mainly because it:
Uses liquid chemicals to dissolve surface oxides
Removes material to improve surface smoothness
Applies a dry powder that is heated to form a durable protective layer
Uses electrical current to remove metal ions
Two machined metal surfaces are pressed together under increasing normal load. Which statement BEST explains why the real area of contact increases with load?
The apparent area of contact increases due to surface expansion
Surface waviness becomes more dominant than roughness
Asperities undergo elastic and plastic deformation
The surface lay changes direction
Which surface characteristic is MOST affected by machine tool vibration during machining?
Surface roughness
Surface waviness
Surface lay
Form accuracy
A surface has a low average roughness (Ra) value but shows poor sealing performance. Which surface feature is MOST likely responsible?
Surface roughness
Surface lay orientation
Surface waviness
Real area of contact
In a sliding contact where the direction of motion is perpendicular to the surface lay, which effect is MOST likely to occur?
Reduced friction due to smoother contact
No change in wear behavior
Increased friction and wear
Increased apparent area of contact
Which advantage of well-engineered surfaces helps reduce noise, vibration, and energy loss in machines?
Customization without changing bulk material
Corrosion resistance
Enhanced performance and efficiency
Efficient load transmission
What is the primary purpose of maintaining proper lubrication on solid surfaces?
To increase surface roughness
To reduce friction and heat generation
To improve surface color
To prevent dimensional changes
Which mechanical component relies on surface contact to distribute load and prevent slipping?
Cutting tools
Bolted joints and frames
Piston–cylinder assemblies
Gears
Why must dies and molds have smooth and durable surfaces?
To reduce material density
To improve thermal conductivity
To ensure accuracy and long service life
To increase surface hardness only
Which term refers to the attraction between similar molecules within a solid?
Adhesion
Adsorption
Cohesion
Diffusion
Cohesion primarily affects which property of a material?
Surface color
Mechanical strength
Electrical voltage
Chemical composition
Weak cohesive forces in solids may lead to:
Improved ductility
Increased flexibility
Cracking and structural failure
Better surface finish
Which type of bonding is responsible for cohesion in metals?
Covalent bonding
Ionic bonding
Metallic bonding
Intermolecular forces
The “sea of electrons” model is associated with:
Ionic bonding
Covalent bonding
Metallic bonding
Hydrogen bonding
Materials with dominant covalent bonding are generally:
Soft and ductile
Hard and brittle
Highly elastic
Easily deformable
Ionic bonding in solids is characterized by:
Electron sharing
Free-moving electrons
Attraction between opposite ions
Weak van der Waals forces
Which material property is typical of ionically bonded solids?
High ductility
Low melting point
Brittle fracture behavior
High electrical conductivity
Intermolecular (secondary) forces are best described as:
Strong atomic bonds
Weak molecular attractions
Metallic electron sharing
Ionic charge transfer
Rubber and polymers mainly rely on which type of cohesive force?
Metallic bonding
Ionic bonding
Covalent bonding
Intermolecular forces
Adhesion is defined as the attraction between:
Similar molecules only
Atoms within a solid
Dissimilar materials or surfaces
Gas molecules only
Which property improves adhesion by allowing better spreading of an adhesive?
Cohesive strength
Wettability
Elastic modulus
Density
Which adhesion mechanism involves surface roughness and pores?
Chemical bonding
Diffusion theory
Mechanical interlocking
Electrostatic attraction
Adhesion due to van der Waals and hydrogen bonding is classified as:
Mechanical interlocking
Physical attraction
Chemical bonding
Diffusion
Polymer chain inter-diffusion across an interface explains adhesion by:
Wetting theory
Diffusion theory
Electrostatic attraction
Mechanical interlocking
Adsorption is best described as:
Absorption into the bulk of a material
Internal bonding within solids
Accumulation of molecules on a surface
Chemical reaction in liquids
In adsorption, the material being adsorbed is called the:
Adsorbent
Adsorber
Adsorbate
Catalyst
Which type of adsorption involves weak van der Waals forces?
Chemisorption
Ionic adsorption
Physisorption
Electrostatic adsorption
Adsorption generally decreases with increasing:
Surface area
Pressure
Temperature
Nature of gas
Which adsorption isotherm assumes monolayer adsorption on a surface?
Freundlich isotherm
Langmuir isotherm
BET isotherm
Henry’s law
